Today, buildings in Germany, Austria and Switzerland are responsible for around 35% of energy consumption and around 33% of CO2 emissions.
Sustainable construction using concrete
The sum total of all buildings should become climate neutral by 2050. However, this can only happen if old buildings are redeveloped in terms of energy use, or replaced by sustainable, new buildings. Redeveloping old buildings is often only possible with considerable limitations. It is also not as effective ecologically as constructing new energy-efficient buildings.
New buildings with larger floorspace, such as apartment buildings, larger developments or commercial or office complexes can currently only be built economically using concrete. So the question becomes: how can construction be achieved sustainably, using concrete?
The dilemma: production of cement and steel as basic building materials for modern concrete buildings is energy-intensive, and releases large amounts of CO2.
Sustainable construction is also possible using concrete: The benefits of Cobiax at a glance
The construction phase
Sustainable building reduces the CO2 load early on, in the construction phase, and not just when fully operational. With Cobiax void formers, the drain on resources is significantly reduced early on, at the shell stage.
The much lower need for concrete leads to less need for transport with this construction material. Concrete is heavy, and haulage is expensive. The reduction in the amount of concrete in the slabs therefore leads to significantly lower CO2 load from transport vehicles, compared to conventional solid concrete slabs.
Sustainable building using Cobiax is financially sound, since the lighter slabs reduce load on the foundations and the load-bearing structure can be designed to be more delicate and lighter than with heavy, solid concrete. (Incidentally, using Cobiax also allows larger spans, meaning the rooms can be designed more open-plan, and converting them for alternative use later is easier.)
If the building is constructed using reinforced concrete, the only way to reduce CO2 load is to reduce the amount of concrete used. The Cobiax void former systems is the ideal building component here. Not only does it reduce the need for concrete in the slabs by up to 35%, it also enables slimmer overall construction and foundations, since the weight of the slabs is significantly reduced. This reduces the need for reinforcement steel and more concrete.
The German Sustainable Building Council (DGNB) draws specific attention to the importance of sustainable materials such as recyclable concrete, but also reduced transport costs and transport routes.
Cobiax voided flat slabs are approved, tried and tested, and safe. They are an easy way to change gear towards more sustainable construction right now.
Cobiax technology has won several awards. Cobiax won the Swiss Environmental Award in the “Technical Innovation” category back in 2010, and in the same year the German Materials Efficiency Award from the German Ministry of Economics and Technology. 2013 saw the Research Award for Sustainable Development, from the Federal Ministry of Research and Education.
All leading architecture and structural planning offices and institutions have the know-how and necessary software systems to plan new projects using sustainable Cobiax voided flat slabs, or to re-imagine existing draft plans using Cobiax technology with little effort.
Cobiax void former products come in different sizes, for slab depths from 20 to over 80 cm.
Climate-neutral construction: an Utopia?
Alternative building materials repeatedly come into play as part of the sustainability debate. Some approaches are worthwhile and appropriate, as long as they are single or two-family houses, such as timber or prefabricated timber.
But when it comes to building thousands of square metres for residential or commercial use, these construction methods reach their limits. At this level, there is no ecological or financial alternative to reinforced concrete structures.
United Nations Campus, Bonn
The building extension at the United Nations Campus in Bonn is a pilot project meeting the gold standard in the sustainable building rating system for federal buildings (BNB).
The bar has been set high – the building has to meet demanding financial, ecological and socio-cultural criteria.
It has been designed using the passive house concept. Even waste heat from the IT hardware in the roughly 100 square metre server room is used.
Cobiax voided flat slabs support this focus on sustainability, and reduce concrete consumption by 600 tons, sparing the environment 50 tons of CO2.
The new training centre is all about a future where aesthetics and functionality combine. Michael Hehl, Arburg managing partner: “We are combining high-tech and innovation with resource conservation and sustainability”. Of course, Cobiax voided flat slabs have been used in such a sustainably designed building complex. So saving 590 tons of concrete and 50 tons of CO2. “With the CO2 saved, you could drive a million kilometres by car,” according to architect Siegfried Schmelzle (Schmelzle and partner).
The New Campus includes 26,000 m2 of floorspace and provides sufficient creativity space for 1,700 staff. Using Cobiax saves 2,250 tons of concrete and 189 tons of CO2. A further effect of lighter slabs is that fewer columns are needed, meaning the office and conference rooms can have a flexible layout at any point.
The Heidestrasse development is being built in central Berlin; already designed conceptually as a particularly sustainable construction project. In the Track building section, more than 100,000 m2 is being built using Cobiax voided flat slabs, reducing concrete consumption by 13,000 tons and CO2 load by 1,100 tons.
Those who are building sustainably today have designed with Cobiax in mind.
Building complexes with the recognised sustainability certificates LEED, DGNB and BREEAM are being built using Cobiax voided flat slabs. Even in the construction phase, these buildings are predestined for social acceptability and future sustainability. The extraordinary cost-effectiveness of the Cobiax system makes it easier for builders, construction companies and architects to set an example for new construction with a consciously ecological focus using concrete.